Modern motor vehicles are equipped with a windshield defroster which is typically part of the climate control system of the automobile. As described in U.S. Pat. No. 5,624,310, to Fredriksson et al ('310 patent), which is incorporated herein by reference in its entirety, a problem which may occur in such an automobile when the vehicle is operated with the climate control system in an air conditioning or defrost mode, then the vehicle is shut off for a short period of time. When the vehicle is restarted, condensation within the evaporator may be blown onto the windshield and cause a fogging of the windshield. The '310 patent addresses this problem by disabling the climate control fan or blower for a period of time until the evaporator has reached an optimal low temperature.
Applicants believe this approach may lead to customer dissatisfaction because the occupants of the vehicle will detect that the blower motor is not operating and may perceive this to be a defective blower motor. Furthermore, the air conditioner compressor does not operate below a predetermined temperature and the selected mode may not be have the climate control system operate in a mode in which the air conditioning system is activated, in which case the evaporator temperature will not reach the optimal temperature. In either case, the blower may not operate for an unsatisfactory time period.
It would therefore be desirable to provide a system and method for defrosting a windshield in a motor vehicle which does not disable the blower motor and which prevents fogging of the windshield.